<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>操作样式表</title>
</head>
<body>
</body>
<script>
  // 不常用操作 html 的样式表，需要的详情见《javascript高级语言程序设计》
</script>
</html>